Apparatus for producing carbon black



March 4, 1958 N. D. STEELE 2,825,633

APPARATUS FOR PRODUCING CARBON BLACK I Original Filed April 8. 1952 2Sheets-Sheet 1 March 4, 1958 N. 4 STEELE APPARATUS RoR PRoDUcING CARBONRLAcR original Filed April e, 1952 2 Sheets-Sheet 2 d M. RMN-MN' T y A Amm .Q A /w?w V M 'I' 7 TW AIAU VJ/V J Y A6 wm. Al WW. u Y u E W m0 A lAAH A .MAA/f -N A m \M.\ u .l|\ wl. VM. y v. "n l"n /f//A/o @N mm. Nm.mm. Nm.

-I M. M. Sm A n mm m H m m MN WN. N. Nm WN Nm. Sm. WN bm.

Unite APPARATUS FOR PRDUCHNG CARBON BLACK Newman Dudley Steele,Lafayette, La., assigner to Godfrey L. Cabot, inc., Boston, Mass., acorporation of Massachusetts Original application April 8, 1952, SerialNo. 231,063. iide and this application August 6, i954, Serial No.

Claims. (Cl. E27-259.5)

This invention relates to processes and apparatus for producing fromliquid hydrocarbons carbon black of novel properties and at improvedyields. in certain respects this invention is an improvement over thatdescribed in the copending application of Friauf et a1., Ser. No.158,226, filed April 26, i950.

To obtain carbon black of desired characteristics at high rates ofproduction and high yields it is necessary to apply the necessary heatto dissociate the liquid hydro carbonaceous raw material in a particularand carefully controlled manner. Numerous processes and varieties ofapparatus have been devised for the production of carbon black, alloperating according to that basic necessity. Of these, many appear toresemble one another but their differences, though Often seeminglyslight, are of fundamental importance.

In the carbon black art an improvement over a known process or apparatuswhich appears as but a modification may in fact lead to an unexpectedand important result, whether by way of significant increases in yieldof known types 0f carbon black or by way of producing new types of blacknot previously known. Such is the case with the process and apparatus ofthis invention.

The mechanism of carbon black formation is very complicated and is notfully understood. it is, however, well known that a hydrocarbon does notinstantaneously divide itself like an amoeba into its components ofcarbon and hydrogen under the action of heat but in fact travels througha variety of metamorphoses, polymerizing in the process. Consequently,it makes a great dierence how and where the heat is applied to thehydrocarbonaceous raw material.

Generally speaking, the particle size, and hence reinforcing efect, ofthe carbon black depend upon the speed and duration of the dissociationreaction and upon the environment in which the reaction takes place.

Thus to upgrade quality by reducing the particle size of the black or toincrease the yield of a known particle size black it is necessary tocause the formation of small particles and to prevent their growth whileunreacted hydrocarbon remains in the reaction zone, all without burningany substantial quantity of make raw material. This is accomplished bythe novel process and in the novel apparatus of my invention.

Various attempts have been made to supply heat and dilution to the makeraw material from a source other than the make material itself. Onesuccessful process for doing so is that disclosed in U. S. LettersPatent No. 2,419,565, Krejci, in which the hydrocarbon raw material isin the vapor state when injected into the reactor. The process of thecopending Friauf et al. application referred to above has beensuccessful for the purpose when producing carbon black from makematerial which is liquid when first injected into the furnace. Bothprocesses, however, have their limitations as to quality and yield ofcarbon black and it is to the production of similar and also differenttypes of black at improved production rates and yields that thisinvention relates.

A feature of the invention comprises a new, simple and inexpensiveunitary burner for fuel and make-hydrocar-v bon with which to establishunique conditions in a carbon black producing reaction zone.

Broadly, the process of my invention consists in introducing into asuitable carbon black furnace an atomized or vaporized make-hydrocarbonthrough a single injector pipe centered in the end wall and extendinglongitudinally of the furnace, simultaneously introducing a combustiblefuel gas from a series of points closely surrounding the hydrocarboninjector pipe but at a substantial distance upstream from the point ofmake-hydrocarbon injection, and flowing an oxygen-containing gas pastthe fuel gas and make-hydrocarbon in suicient volume to burn all of thefuel gas and a small proportion of the makehydrocarbon.

in this connection a novel burner is employed which is characterized bya central oil pipe with a discharge nozzle at its end, in combinationwith a gas pipe concentrically disposed about the oil pipe in spacedrelation thereto, and means within the gas pipe for causing gas to flowlongitudinally back and forth within the burner in heatexchange relationto the reaction space of the furnace and to be directed so as to envelopthe oil spray discharged from the nozzle.

It is important that the fuel gas be introduced in a relatively confinedcombustion space and at sufficient distance upstream of the point ofmake-hydrocarbon injection in order that the fuel gas may be burnedbefore reaching the hydrocarbon spray. To insure adequate burning of thefuel an excess of air over the theoretical amount required is introducedand hence some small amount of the hydrocarbon will inevitably be burnedas well.

In fact, it is one of the advantages of my invention that by reason ofthe critical relationship between the points of introduction of the makeoil, fuel gas and air, a wide variety of operating conditions may beestablished to produce the many different types of carbon black at adegree of elliciency heretofore not obtained. As the dissociationreaction by which the make-hydrocarbon is converted to carbon black islargely effected by heat transfer from the fuel gas combustion productsand since the oxygen containing gas will be air or oxygen diluted withtail gas or other inert gases, there will be a substantial volume of hotdiluent gas to mingle with the make-hydrocarbon and this is effective toprevent growth of the carbon particles.

The desired atmosphere is obtained by the steps of mixing fuel gas andair by jetting the gas into the relatively slow moving body of air in acircle immediately around the make-hydrocarbon injector pipe asubstantial distance upstream from the point of injection of themakehydrocarbon. There is thus produced a highly turbulent and very hotmass of combustion products owing past the spray of raw material withresultant heat transfer to the spray of maximum efficiency andconcomitant dilution effect.

The process of my invention is particularly adapted to the use of heavyoils and tars, referred to generally herein as residual oils," as thesource of carbon black. Such residual oils are obtained from a widevariety of hydrocarbon distillation and cracking operations, includingthe destructive distillation of coal. They are characterized by beingnot fully vaporizable under atmospheric pressure and some of them willcrack to carbon before as little as 59% has gone overhead. Of these lprefer to use the oils having a hydrogen to carbon ratio of from about0.75 to about 1.25 and a mean molecular weight of from about 225 toabout 559. Such oils will also usually have an A. P. I. gravity of notmore than 10, a viscosity in excess Patented Mar. 4, 1958V asasgoasw- 3ofc-3 0.r SSUlSaybolt. secondscUniversaDc at ..2 lt'lcl'tand..w aConradson carbon residue in vexcess of 1.5.

Typical residual oils useful in the practice of thisinventionare-listedtin vTable I following: fr:

Table l Com-adson Carbon Residue, percent;V

Aver- Viscosity, asu;

.l Source Petroleum The various features of my invention will bestbeun-`l` derstood and' appreciated from the following description of 'atypical' embodiment of my novel apparatus by the` use Vof whichthe.process of my invention may advantagei ouslybeecarriedout;'selected forpurposes of illustration and shownin theaccompanying drawings in which:

Figurel is a diagrammatic'view, partly in section Van partlyin side"elevation;

Figure 2 is a View in elevation of the burner;and

Figure 3 is a detail, shown in cross sectionfof'the gays headwithperipheral orifices and' the atomizingl tip:

Th'erfurnace herein shownv includes an"e1on`gatedreac="` tioncharnber10,- which may be of'any convenient .'cro'ss" sectional shape;preferably cylindrical, having'a steel shell 12,7*acourse'ofinsulating-brick 14and a lining 16of highly' refractorymaterial. At the left orinlet 'end'the"" reaction chamber vlll-tapersrearwardly in al section 18to ancinlet'passage'orthroat 20 of lesserdiameter thanthat* of the reaction chamber of the furnace and whichprovides a confined combustion' space andA is the'only inlet'l to theIfurnacerThetaper'of the section'lSis im''A portant'in that itapproximates` the-angle ofthe oil'spray cone 'and thuspronrotesv moreeicient radiant he'at'trans ferito lthefoil spray. A burner pipe 22 iscenteredin the f furnace throat and extends completely through thecombustion 'space-ofthe throatv into the furnace and" at leastto thetapered section `18.-

The' reaction chamber 10 'is open at fthe *end-opposite thefbu'rnerandwith thisl communicates a conventional-'- ue' pipe124j for 'the passageofY the gaseous productsI of combustion and entrainedcarbonblack tothe"collectors'" for'a portion of fits. length1by` a larger gas pipe 22and '5 an'extensio 23'fliaving`l'a gas-"-tightvcap 25 at l'its endlo-*Jcated within 'the'.furnace A Arelatively short intermedi-"'1-ate=-fpipe` 26is -concentrically disposed approximately"equidistantfbetween the outer lgas pipe extension 23 'and oil -pipe 21and is threaded-at itsupstream end into'the` 60 shouldered inner wall ofpipe 22 by a gas tight seal' 28.12 completely-around its circumference.This middle .or Ain.

termediate .pipe 26 is soplacedathat itsdownstream endY f. opens in achamber provided by `thecap -275 thus providing g forthe ow of gasrstalongthe annular passage formed' ..6

between theoil pipe 21 and the intermediate :pipe 426 and.` then backalong theouter annular passage formedbetween thev gas pipehextension 23and the intermediate pipe 26 Pipe 22and its extension 23 a're connectedby gas head 70 providedwith a' plurality of oi'iiice's 32 disposed'equi-` distantzlfroin one another :aroundits periphery." This .gasheadf'iE mayv be astandard-'collana sectiou'of pipepr any f othe'ifsuitable l device? vThe gas vpipe 21 is extended into-the...gas upipeJand `at the -other-intothe1cap -25- and. having a reducing bushing 36 inits outlet end or discharge nozzle.

It can be seen that the burner assembly illustrated is very simplyconstructedand-can quickly and easily be disassembled for cleaning andfor replacement of parts andfrthat 'parts 'of different sizesran'drdesign 'can easily'be.` substituted. It .will also be readilyapparent that the con-Y structionof the' burner may be"modifiedwithoutdeparting from the spirit of my invention.

For example, pipe 22 could be of continuous length drilled withgasorifices and makingpossible theomission of-`gas1head 28. Likewise;instead of extending the oil pipe by the nipple 34 the oil pipe could becontinuous'. Alternatively, an atomizingnozzle-.of the filared inlet ororifice type may be provided at the discharge end of the oil pipe 21. Y

They numberV and size of milices-32 are `determined largely-bythecombustion conditions desired; Generally'I speaking,nit is advantageousVthat as 'many oricesf'ofVasH large diameter 'aspossible be provided. fHowever, when' .i extreme turbulence is required fewer orifices ofsmallerf' diameter may advantageously.beemployedtAsheref'lfshownftheworifices vare directed radially from the burnerApipe .but theyi mayV be directed downstream i at anangle'li'f to `the'radius .orahelically to impart a spinning motionto theflgases.' i

Oilxp'ip'elZlterminates outside the furnacein a mixingl'f chamber-.40where the'liquid hydrocarbon make material; fpreferably-preheated toimprove its fluidity, and supplied/li throughiinlet pipe42 isinitiallyaspirated'by and mixedil withzair,A steamorrother gaseous.atomizing'uii or'mixl ture thereof, introduced through pipe44:1Themixin'gfi chamberv 40 Ymay. beof any conventional design whichemploys the :two-fluid atomization. principle.` 1 A number oficommercialmixers are readily .available .andLsatisfacH-v tory for the 4purposes ofmy invention.

Gaspipe 22.embraces Vthe central oil. pipe 21 foria portion onlysof itstotal length but terminates'outsideofthe? furnace.` in a gas tight seal46. Union' 48 is provided for.'l ff -thezintroduction of a combustiblegas into theV gas stream of thepipe'22.

Inoperation the make-hydrocarbon atomized with a l gas=such as air,steam or a combustible or inert gas, ini`- 5 chamber 40 Yis dischargedfrom pipe 21 into furnace 10.

in the formof a conical spray composedof minute dropy letszofoil.; Attheisame'timeia combustible fuel .gas'such'f as :naulralze-gas, coke`oven gas,1 hydrogen.V or vaporizede'ifk or atomized liquid hydrocarbonis introduced'finto .the if 0 outer rendi lofthe confined combustionspace of thevfurnace through'` Vgas headintheiorm'of' jets that are@directed 'radially and.. outwardly inrespect to the'lprolv jected axisofthe oil supply.` vAirfilows into fthe furnacel.:A under.y low. ipressure r. (about. 4-8 A-inches 'ofy water); from 5 heade1r50f`suppliedfromv 'duct-52 through thecombustion #l spacel of thefurnacelthroat-I 20L and`thence past .gas-head; il 30.-.1: The? rate ofairflow is determinedrprincipally by the rate of'fuel'lgas flowandsecondarily .byzthe rate ofmake- 1' hydrocarbon flow, it .being.the'robject to supply suflicientf air=fto .buru;s al1 of Ythefuelgas'Jand-:a small. portion of the oil. The gas head 30 beingsuflcientlylfarlupstreamf. fromfthefoilrpipernozzle@toinsurefthatsubstantially all of 'the` :gasfis burned; .principally'finthe: vconfined combustion-spa'ce .provided1 Vby they .throat120,'rbeforeit cani-'l 5 make'contac't witharthefloil spray.'.:nThe `hot products`ofi" combustionxheat-'thelburner'in passing Ithrough the 'come' bustonspacec ands then'. mingle .intimately with theoil ispray:.byvirtue.offthefrespective-'con1ponents of owsothatathei.:'carbonblackzforming `reaction occurs almostsimnltaneouslyflwith the introduction of the.r oil into ithe reactionzone. Excess air: not 'needed to burn 'the'v fuel;ygaswilltioffcourselburn a small amount of thefoil."

The'distancebetween-the oil pipftip' 'and the" plan'e of` l orices r`322iin subject to `considerablevariation 'depending "IL upon thecharacteristic'slof the'bcarbo'n black toibepror senses duced. It willnot ordinarily be less than about 6 inches and may be as great as about22 inches. ln any event the distance must be suiiicient thatsubstantially all of the gas will be burned before reaching the make oilspray but not so far that substantial heat will be lost from thecombustion products before mixing with the oil spray.

An important feature of the burner of my invention is that ofcirculating the fuel gas to the discharge tip and back in reversing owalong the outer conduit in an annular countercurrent stream in contactwith the wall of pipe 26 before injection into the furnace through gashead 30. Being exposed to the intense heat generated by the burning fuelthe extension pipe 23 would soon fail were it not for the coolingobtained from the circulating fuel gas. At the same time the fuel gasbeing exposed to the heat transmitted through the walls of pipe 23 ispreheated for higher thermal efiiciency.

Results obtained by the practice of my invention are set forth in thefollowing examples of runs illustrative of many made in furnaces 5.65ft. and 10.65 ft. in length. 1t will be noted that significant increasesin yield were obtained by the novel process and in the new apparatus ofmy invention and that such increased yields were consistently obtainedwhile maintaining and even improving the quality of the product. Inthose cases where yield was not increased a very great increase inproduct quality, notably in abrasion resistance in rubber, was the usualresult.

charge nozzle of the burner, and a cap at said discharge nozzleproviding an opening connecting the annular fuel gas passages forreversing ow of gas in the burner.

2. In a carbon black producing furnace, a burner hav- 5 ing a centraloil pipe with a discharge nozzle at its end for delivering gas-borne oilto the furnace, an interme` diate pipe spaced from the oil pipe andforming an inner annular passage therewith and having an inlet for fuelgas located at its outer end, an outer pipe spaced from 10 theintermediate pipe and forming an outer annular passage therewith, a capsecured to the oil pipe and said outer pipe and providing a connectingchamber between the ends of said annular passages, and a gas headlocated at the upstream end of the outer pipe and having a ring ofoutlet orifices for discharging fuel gas after the latter has end, abifluid mixing device at its other end, au outer pipe terminating in acap, an intermediate pipe disposed between the innermost and outer pipesand opening within the cap at its discharge end, a gas-tight sealsecuring the intermediate pipe to the inner wall of said outer pipe, anda gas head surrounding the outer pipe and having a plurality of orificesdisposed about its periphery, whereby atomized oil may be delivered fromthe spray nozzle and a combustible mixture may be Properties in coldMake T2 Surf. Increase rubber, percent of Make Fuel Gas, Air, Oil.Yield, area Gas Head Standin yield standard Run No. Oil, F. MCF] percent#/gal. (sq. in.l Furnace Size Orlces, ard 1 over gaL/hr. hr. comb. g.)inches std. av.

(#/gal.) Abrasion 300 res. modulus 60.2 1,998 42.2 22. 6 4. 33 57 565'X18' 12% HAF 0.83 102 125 38 2, 913 39.1 14 5l 4. 08 74 5 65'X1B' 12%HAF 0. 58 101 111 39 3.000 36.6 8.24 4.60 54 E 65x18' 12% HAF 1.10 92109 39.9 2,997 36.5 7.73 4.55 5l 5 65Xl8' 12% HAF 1.05 101 113 39. 9 4,006 47 7. 49 3. 88 73 5 65xl8' 12% HAF 0. 38 113 114 59 3. 998 47 7 6.12 5. 35 44 5 65xl8' 12% HAF 1.85 78 112 60.8 3, 001 49.1 8.85 3. 46 69l0 65Xl8" 24% HAF -0.04 112 97 40. 1 3, 989 47. 1 7. 94 3. 87 71 1065x18" 24% HAF 0.37 106 94 59. 5 4, 000 49 7. 22 4. 79 47 10 65xl8' 24%HAF l. 29 98 95 59. 4 3, 983 48. 4 6.45 4. 63 49 10 65xl8" 24% HAF 1.1396 90 69.8 2, 998 38. 7 6. 60 5.28 33 10 65'X27' 12% FEF 1. 03 97 11691.4 2, 994 40. 7 6. 35 5. 54 31 l0 65x27' 12% FEF 1.29 92 103 69. 7 2,998 33. 9 2. 02 6. 25 27 10 65x27' 12% FEF 2.00 93 106 60.0 3, 000 32. 60. 97 5. 50 30 10. (i5/x27' 12% FEF 1. 25 105 114 61. 2 3,001 5. 30 5.66 28 10. 65X27' 12% FEF 1. 41 93 116 61.7 3, 001 8. 09 4. 95 36 l0v65x27" 12% FEF 0. 70 106 117 60. 1 3, 008 S. 64 5. 48 36 10. 65x27' 12%FEF 1. 23 101 119 60 3. 000 6.30 4. 55 33 10 65x27' 12% FEF 0.30 103 11469.1 3, 000 11.7 5.02 39 10. 65X27' 12% FEF 0.77 104 108 59. 9 3. 000 9.2 5. 60 39 10. 65x27' 12% FEF 1. 35 106 11S 60. 1 3, 000 9. 15 5. 29 3710. 65X27' 12% FEF 1. 04 103 113 i The standards used are Vulcan 3 forHAF and Sterling SO for FEF, both produced in accordance with theprocess disclosed and claimed in Friaul' et al. application Ser. No.158,226. The yield figures for the standard are as follows: HAF-3.5 lbs.per gal. of make oil; FEF-4.25 lbs. per

gal. of make oil.

It is noteworthy that by following the process and utilizing commercialsize apparatus of this invention yields of carbon black product wereincreased on the average by almost one pound per gallon of raw material,or by about 20%, a truly significant increase. Further more, when yieldwas not increased by any important amount, the qualities of modulus andabrasion resistance were substantially increased.

This application is a division of my co-peuding application Ser. No.281,063, tiled April 8, 1952, in which is claimed a novel process ofmaking carbon black that may be carried out by employing the apparatusherein described.

Having thus disclosed my invention and described in detail preferredembodiments thereof, I claim and desire to secure by Letters Patent:

l. In a furnace for producing carbon black, a burner having a dischargenozzle at its inner end, an oil pipe leading thereto, and spacedconcentric gas pipes surrounding the oil pipe and providing parallelannular fuel gas passages, the outer gas pipe having discharge oriceslocated a substantial distance upstream from the disconducted throughthe burner in reversing flow surrounding the inner pipe in which the oilpasses to said spray nozzle.

4. In a furnace for producing carbon black comprising an elongatedreaction chamber having a throat of reduced diameter at one endproviding combustion space,

a burner having an inner pipe for discharging a combustible oil mixtureinto the reaction chamber, the said inner pipe passing through thethroat and being surrounded in the throat by concentric pipes withconnections arranged to provide passages for reversing ow of fuel gas inthe combustion space of the throat, said connections including means fordirecting the fue] gas from the end of the inner concentric pipe intothe end of the outer concentric pipe, and a gas outlet in the outer ofsaid concentric pipes located to discharge into the furnace throat.

5. In a furnace for producing carbon black, a burner comprising acentral pipe having at the outer end of the burner a central dischargenozzle for a combustible oil mixture, a cap surrounding said nozzle, anouter pipe threaded into the cap in concentric relation to the centralanfintermediate pipeconcentric -withuthe outerpipel so as to formparallel annularpassages within lthe-burneropenoxv. of vfuel gasufromthe capito the oricesof the-'outer'.

pipexandlconsequent heating. of ythe gas;

References Citd in th le Vvofthi `patentY UNITED STATES. `PATENTS l 8.;Moork .'Y...- ...July 12,:190'4- Frost ,Dec.5, 1922 Miller June.f24,y193() y Graham -Oct. 12,1943- 2 Zink Y. Feb. 225 A1949 Swegart Aug. 17,1954 FOREIGN PATENTS A Belgium Aug. 31,1950"y Great vBritain Nov. 4,1953r

1. IN A FURNACE FOR PRODUCING CARBON BLACK, A BURNER HAVING A DISCHARGENOZZLE AT ITS INNER END, AN OIL PIPE LEADING THERETO, AND SPACEDCONCENTRIC GAS PIPES SURROUNDING THE OIL PIPE AND PROVIDING PARALLELANNULAR FUEL GAS PASSAGES, THE OUTER GAS PIPE HAVING DISCHARGE ORIFICESLOCATED A SUBSTANTIAL DISTANCE UPSTREAM FROM THE DISCHARGE NOZZLE OF THEBURNER, AND A CAP AT SAID DISCHARGE NOZZLE PROVIDING AN OPENINGCONNECTING THE ANNULAR FUEL GAS PASSAGES FOR REVERSING FLOW OF GAS INTHE BURNER.